Mechanical rectifier.



- UNTTED sTATEs PATENT carica.

RAY P. JACKSON, OF EDGEWOOD PARK, IPENNSLYVANIA, ASSIGNOR TO WESTINGI-IOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

MECHANICAL BECTIFIER.

1 Specification of Letters Patent.

Patented sept. 26, 1916.

`Application iled '.Tune 9, 1914. Serial No. 843,949.

vdevice of the character specified that will be effective in operation and substantially free from sparking throughout widel varia.- tionsof load, frequency, and wave form.

Referring to the accompanying drawing, Figure 1 is a diagrammatic\v-ie`w of a rectifying apparatus'embodying my invention; Fig. 2 is a diagrammatic View of a modiication of the apparatus shown in Fig. 1; and

Fig. 3 is a diagram illustrating my invention as applied to a rectifier of the vibrating type.

Hitherto, in common types yof mechanicall rectiiie'rs, it has been customary to allow current from one wave to flow through a given path untila` point at or near the end of the current wave was reached. Connection was then broken and,-if thebreak camev at any but the point of zero current, sparking would ensue. If the point of break were too early, the current wave would not have ceased iowing and ifgtlie point of break were too late, reverse `current would have set in from the succeedingwave of undesired polarity. While itfis entirely possible to secure sparkless" operation with constant voltage, load, frequency, and wave form, a change in any one of these factors may so Aalter the point of zero current as to prevent sparkless rectification.

By my invention, instead of closing a given current path during waves of one polarity and opening said current path durlng waves of the opposite polarity, I provide a current path ofy low resistance for waves of one polarity and a path for the waves of the other polarity comprising a conductor of the vfirst class of comparatively lownn'resistance when cool but of extremely high resistance when hot, said conductor having-.-very small heat capacity and constituting a goodheat-radiating means. Such a Aconductorfis `found in a fine iron filament 4 .'moi'inted in a' hydrogen atmosphere, as in -thei'lballast resistances used in Nernst lamps.

By this mode of operation, the circuit is never broken, but waves .of the undesired polarity are caused to flow through the rst class conductor and the latter keeps down the amount of current which can How by its exceedingly high resistance, when heated to an appreciable amount.

Referring to the form of my device shown 1n Fig. 1, 4 is any suitable source of alternatlng current, such, for example, as the secondary winding of a transformer 5, provided with a primary winding 6 supplied with alternating current from the mains 7 and 8. The terminals of the secondary winding 4 are connected, respectively, to slip rings 9 and 10 mounted on a shaft 11 driven in synchronism with the frequency of the source`4 by means of a synchronous motor 12. Two rectifying devices 13 and 14, of the rotating type, are mounted onthe shaft 11 and rotate therewith. Current from the left hand terminal of the source 4 is supplied to the slip ring 9 by a brush 15 and thence flows through a shaft conductor '7 toa bond wire 18 connecting four rotating segments 19 in the rectifying device 13. Each of the segments 19 covers an arc of substantially 45 in length. Interposed between the conducting segments 19 lare similar conducting segments 20, each of which is connected to a bond wire 21, which, in turn, is connected to a conducting segment 22. Four brushes 23 are adapted to make contact successively with the segment 22, and each of the brushes 23 is connected to a terminal of a ballast lamp 24. The other "terminals of the ballast lamps 24 are connected'to the left hand terminal of the source 4. In a similar manner, current from the right hand end ofthe source 4 flows through a brush 16 and the slip ring 10 to a shaft conductor 25 and thence to a bond wire 26 connected to conducting segments 27. Interposed between the conducting segments 27 are conducting segments 28 connected to a bond wire 29 which, in turn, is connected to a" segment 30 that is adapted to make contact with brushes 31. Each of the brushes 31 is connected to a. terminal of the ballast lamps 32, and the remaining terminals of the ballast lamps 32 are connected to the right vhand end of the source 4. The armature of the synchronous motor 12 is supplied with alternating current from thev source 4 by means of the shaft conductors 17 and 25 and is provided with any suitable direct-current excitation derived, for eX- ample, from a load battery 33.

Having thus described the construction of the device of Fig. 1, the operation is as follows: Then a current wave of the desired polarity is flowing from the right hand end of the source 4, a low-resistance path to the terminal 34 of the load 33 is supplied by means of a conducting segment 27 and the brush 35. At the same time, the wave of .undesired polarity, flowing from the left hand end of the 'source 4 will encounter a conducting path of comparatively high resistance made up of one of the ballast lamps 24, one of the brushes 23, the conducting segment 22, bond wire 21, one of the conducting segments 20 and a brush 36. The resistance of this path rises very rapidly because of the presence therein of the ballast lamp 24 and, accordingly, very little current of the undesired polarity is allowed to reach the point 34 and flow through the load 33 to the mid point of the source. A half cycle later, the operation is reversed; a low-resistance current path is provided through the rectifying device 13 and a comparatively high-resistance current path is provided through the rectifying device 14.

Referring to the form of my device shown in Fig. 2, the terminals of a source of alternating current 37 are connected to slip rings 38 and 39 mounted on a shaft 40, r0- tated in synchronism with the frequency of the source by means of a synchronous motor 41, all as shown and described in Fig. 1. Mounted on the shaft 40 and adapted to rotate therewith are rectifying devices 42 and 43 comprising bond wires 44 and 45 to which are connected segments 46 and 47, alternate segments having a ballast lamp 48 inserted in their connections to the bond. BrushesW4 49 and 50 bear upon the contact segments 46 and 47 and are connected to the terminal 51 of a load 52, the other terminal of which is connected to the mid point of the source 37. The adjustment is such that, when the brush 49 is bearing upon a segment in direct connection with its bond wire, the brush 50 is bearing upon a segment which is connected to its bond wire through a ballast lamp, and vice versa. Accordingly, waves of the desired polarity from either terminal of the source 37 are permitted to pass to the load 52, while all waves of the undesired polarity are suppressed. I consider the form of my device shown in Fig. 2 superior to that shown in Fig. 1 since the connections are` much simpler, fewer brushes are employed, and the ballast lamps are enabled to dissipate heat much more rapidly because of their rapid motion through the air.

Referring to the form of my device shown in Fig. 3, the terminals of a source of alternating currents 53 are connected to ixedl contact members 54 and 55 which are adapted to make contact, respectively, with spring-mounted contact members 56 and 57 of an armature 58 that is pivotally mounted at a point 59. The ends of the armature 58 are adjacent to like poles of a pair of electro-magnets 6() and 61 which are energized by alternating current from the source 53. A unidirectional flux isset up in the armature 58 by a winding 62 that is supplied with direct currentfrom any suitable source, such, for example, as a load battery 63. The structure of Fig. 3 described up to this point is not of my invention but is described and claimed in U. S. Patent No. 1,184,233, issued to the Westinghouse Electric & Manufacturing Company, May 23, 1916, on an applicationl filed by Edgar Giglio. Connected between the contact member 54 and the terminal 64 of the load 63, is a ballast lamp 65 and, in a like manner, connectedbetween the contact member 55 and the terminal 64 is a ballast lamp 66. Then the armature I 58 is caused to vibrate in synchronism with the frequency of the source 53, contact is made between members 54 and 56 when waves of the desired polarity are flowingwhen waves of like polarity are flowing from A the right hand end of the source 53. When contact is made between contact members of either of these pairs, a low-resistance path to the load is provided through the body of the armature 58. Whenycurrent of the desired polarity ceases to flow from either terminal of the winding 53, the corresponding pair of contacts are separated and the only path open is through one of the ballast lamps 65 and 66. Accordingly, the amount of current which can flow from the undesired waves is greatly diminished.

While, throughout this description, I have disclosed the use of the` ordinary ballast lamp comprising a ne iron filament mounted in an atmosphere of hydrogen or other suitable inert gas of high specific heat and good heat conductivity, I do not desire my invention to be limited thereto, as I may employ, in place of the ballast lamp, any desired resistance element having similar characteristics.

While I have shown my invention as 'embodied in three distinct forms for purposes of illustration, I do not desire to have it restricted thereto but wish it to cover broadly any form of rectifier wherein a current path of 'low resistance is provided for waves of the desired polarity and a current path comprising a resistance element composed of a conductor of the first class of small heat capacity and high heat dissipa= tion is provided for the current waves of undesired polarity.

I claim as my invention:

l. The method of deriving a unidirectional current -from an alternating current which comprises inserting a resistance element of the first class and of small heat capacity in the path of alternating current Waves of the undesired polarity.

2. The method of supplying unidirectional current to a load circuit from an alternating-current supply ,circuit which comprises connectin the two circuits through a resistance e ement which is a connections when current waves'of one polarity ductor of the first class and shunting said' Aresistance element by a low-resistance circuit during the half cycles when the. alternating current is of the desired polarity. el,

3. The method of supplying substantially unidirectional current to a load circuit from an alternating-current supply circuit which comprises connecting the two circuits through a. ballast type resistance element and lshunting said resistance element by a low-resistance conducting path during each half cycle when the alternating current is of the desired polarity.

4. The combination with a source of alternating, current, of a load circuit, connections between the 'terminals of the source and. the terminals of the load, respectively, two conductin elements, one'of low resistance and the ot er including a resistance member which is a conductor of the first class, and

means for inserting one of said elements in one of said connections when current waves of one polarity are flowing and for inserting the other of said elements when current waves ofthe other polarity are flowing.

5. The combination. with a source of alternating current, of a load circuit, connections between the terminals of the source and the terminals of the load, respectively, twoconducting elements, one of low resistance and the other including a resistance member which is a conductor of the` first class and of small heat capacity, and means for inserting one of said elements 1n one of said con-` are iiowing and for inserting the other of said elements when current waves of the other polarity are flowing.

6. The combination with a source of alternating current, of a load circuit, connections between the terminals of the source and the terminals of the load, respectively, a plurality of conducting members of low resistance,

a like number of conducting members of high resistance and of the ballast type, and means for inserting the conducting members of low resistance in lrotation in one of the connections between the source and the load when current waves of one polarity are flowing and for inserting the conducting members of high resistance in rotation when current waves of the other polarity are flowing,

7 The combination with a source 'of alternating current, of a load circuit, connections between the terminals of the source and the terminals of the load, respectively, a plurality of conducting members of low resistance, a like number of conducting members comprising conductors of the first class and of high resistance, and means for inserting the conducting members of low resistance in rotation in one of the connections between the source and the load when current Waves of one polarity are fiowing and for inserting the conducting members of high resistance in rotation when current waves of the other A polarity are flowing.

8. The combination with a source of alternating current, of a. load circuit, connections between the terminals of the source and the terminals of the load, respectively, a plurality of conducting members of low resistance, a like number of conducting members comprising conductors of the first class of `high resistance and small heat ca acity, and means for inserting the conducting members of low resistance in rotation in one of the connections between the source and-the load when current waves of) one plurality are flowing and for inserting the conducting members of high resistance, in rotation when current waves of the other polarity are flowing.

9. y The combination with a source of alternating current, of a load circuit, connections ing an even number of conducting segments and a slip ring, low-resistance connections betweenalternate segments and the slip ring, connections-comprising conductors of the first class and of small heat capacity between the remaining segments and the slip ring, means for rotating the commutating device in synchronism with the frequency of the source, a brush bearing on the segments,

and a Lconnection from one'terminal ofthe source through the commutating device and load to the .other terminal of the source.

11. The combination with .a source of alternating current, of a load, a pair of rotatably mounted commutating devices, each comprising an even numberv of conducting segments and a slip ring, low-resistance connections between alternate segments and the slip ring, high-resistance connections, comprising conductors of the iirst kclass having small heat capacity and high radiating capacity, between the remaining segments and the slip ring, means for rotating the commutating devices in synchronism with the frequency of the source, a brush bearing on each segment, connections from each terminal of the source through the commutating devices, respectively, to one terminal of the load, and a connection from the other terminal of the load to substantially the mid point of the source, the adjustment of the brushes being such that, while a circuit is closed through a low-resistance path in one commutating device, it is closed through a high-resistance path in the other commutating device and vice versa.

l2. The method of obtaining substantially unidirectional current from a source of alternating current which comprises inserting a device of low resistance in the path of current iow during waves of one polarity and inserting a conductor of the irst class and of small heat capacity and vhigh radiating capacity in the path of current flow during waves of the other polarity, whereby the quick rise in resistance of the first class conductor greatly diminishes the flow of current from waves of the undesired polarity.

13. The combination with a source of alternating current, of a load, connections between the terminals of the source and the terminals of the load, means, including lowresistance conductors, for permitting heavy current flow from the source through the load during current waves of one polarity, and means, including resistance elements composed of conductors of the irst class and of small heat capacity for permitting only small current lowduring current waves of the other polarity.

14. The combination with a source of alternating current, of a load, connections befrom each terminal of the source to one ter-y minal of the load, a connection from vthe other terminal of the load to substantially the mid point of the source, means, including low-resistance conductors, for alternately allowing heavy current flow from successive current Waves from each terminal of the source, and means, including resistance elements composed of conductors of the first class and of small heat capacity, for allowing only small current iow from each terminal of the source when there is heavy current flow from the other terminal.

16. The combination with a source of alternating current, of a load, connections from each terminal of the source to one terminal of the load, a connection from the other terminal of the load to substantiallythe mid point of the source, means, including low-resistance conductors, for alternately allowing heavy current flow from successive current waves from each terminal of the souce, and means, including ballast lamps, for allowing only small current flow from each terminal ol the source when there is heavy current flow from the other terminal.

In testimony whereof, I have hereunto subscribed my name this 23rd day of May, 1914.

RAY P. JACKSON. Witnesses:

A. M. LUNDY', B. B. HINES. 

